Perhaps the most common method of positioning multiple contact terminals in the nonconductive housing of an electrical connector is to employ snap latches on the terminals to engage surfaces on contact receiving channels in the connector housing. For many applications, this approach is quite satisfactory and mass assembly apparatus for economically loading snap latch terminals in housings are commonly used.
In some applications, however, the snap latch features on both the terminals and the nonconductive housings do pose problems. For example, the snap retention features do require space and for connectors having a closely spaced terminals, the retention geometry can become a problem. The snap retention features also leave open passages between the front and back of a connector. These open passages must be sealed for certain applications. For example, a sealed connector can require the use of separate seals for each terminal passage or cavity.
Another application in which the open passages required by retention features can pose problems is the use of secondary molding operations to fabricate the final product. One common example of a secondary molding operation is an overmolded connector in which a material, such as PVC, is molded over the connector and the end of a cable attached to the connector after the cable wires are terminated to the connector or plug. Cable assemblies of this type are commonly used for computer peripherals. If the terminals cavities remain open, due to the presence of the snap latch retention features on the terminals and the housing, the overmolding material can flow through these passages and foul or contaminate the mating surfaces on the terminals and the nonconductive housing. One approach for preventing the overmolding plastic from entering the mating side of an electrical connector is to employ two molding operations. The first overmolding step is a low pressure injection molding operation in which the overmolding plastic is injected into the terminal cavities at a pressure that is small enough to prevent plastic from reaching the mating side of the connector. The overmolded material is then allowed to solidify, and a second higher pressure overmolding step is used to form the final configuration. However, this two step procedure adds time and expense to the manufacturing operation.
Another technique that can be used to overcome the problems associated with snap latch geometry is to insert mold terminals in a nonconductive housing. The material forming the nonconductive housing flows around the terminals so that the rear of a connector can be completely isolated from the mating side of the connector. Two examples in which a plurality of terminals are molded in a nonconductive connector housing are shown in U.S. Pat. No. 4,865,562 and U.S. Pat. No. 5,184,963. This latter patent describes how contact terminals are maintained on desired center to center spacing on carriers and the housing is then molded around the terminals. After insert molding the contacts, including the carriers, are bent so that reliefs at opposite ends of the contacts allow removal of the carriers by either cutting or bending so that the contact material breaks off between the ends of the contacts and the associated carriers. However, the ends of these contacts extend well beyond the insert molded housing.
In some applications, contacts or leads must be cut adjacent to the housing. This requires an additional die cutting step with an attendant manufacturing cost. U.S. Pat. No. 5,236,375 shows a connector in which carriers are cut immediately adjacent to an insert molded housing. U.S. Pat. No. 5,038,468 discloses another approach in which carriers or connecting ties are cut in the mold itself by using a three piece mold with a punch that severs the carriers upon initial closing of the mold. The final connector housing includes openings formed by the punches. This approach, however adds additional complication to the mold tooling and conventional molds could not be used.
None of these approaches permits the removal of an external carrier strip after an nonconductive housing has been insert molded around the terminals without the use of additional die cutting tooling in applications in which substantial portions of the terminals do not extend well beyond the housing. None of these approaches permits manufacture of a connector in which the ends of terminals are recessed from the end of the housing and are not flush or exposed where they cannot come into contact with other conductive surfaces, such as external shields, during mating and unmating. Furthermore these approaches are not compatible with the use of conventional molds for insert molding the connector.